Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A library management system uses Azure SQL Database. The Books table has 500,000 rows with columns: BookID (primary key, clustered), Title, Author, ISBN, PublishedYear, CopiesAvailable. Queries frequently filter by Author and then sort results by PublishedYear in descending order. Which indexing strategy will most improve query performance?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Create a nonclustered index on (Author) INCLUDE (PublishedYear, CopiesAvailable, Title).
This index covers the filter on Author but does not specify the sort order on PublishedYear. The database may still need to sort the results, which is less efficient.
B
Distractor review
Create a nonclustered index on (PublishedYear) INCLUDE (Author).
This index is ordered by PublishedYear, but the primary filter is on Author. The database would need to scan or use lookups for each Author, which is inefficient.
C
Best answer
Create a nonclustered index on (Author, PublishedYear DESC) INCLUDE (CopiesAvailable, Title, ISBN).
This index is sorted by Author first and then PublishedYear descending, perfectly supporting both the filter and the sort. Included columns make it covering.
D
Distractor review
Create a nonclustered columnstore index on (Author, PublishedYear, CopiesAvailable, Title, ISBN).
Columnstore indexes are designed for large scan-heavy analytical queries, not for point lookups and sorted retrieval of few rows. This would not improve performance for this OLTP-style query.
Common exam trap
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Technical deep dive
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Related practice questions
Related DP-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A data engineer needs to process streaming data from IoT devices and store the results in Azure Data Lake Storage for long-term analytics. The data must be processed in near real-time to detect anomalies and trigger alerts. Which Azure service should the engineer use for stream processing?
Question 2
A data engineer needs to query data stored in CSV files in Azure Data Lake Storage Gen2 using T-SQL in Azure Synapse Analytics, without loading the data into the database. Which feature should they use?
Question 3
A data engineer needs to process raw clickstream data from multiple websites that is stored in Azure Blob Storage as JSON files. The processing must run automatically every hour, transform the data into a structured format for reporting, and handle schema changes in the source data without manual intervention. Which Azure service should be used?
Question 4
A data engineer is designing a data lake architecture in Azure. They plan to first ingest raw data from various sources into a landing zone in Azure Data Lake Storage Gen2. Then they will clean, validate, and deduplicate that data in a second zone. Finally, they will create aggregated, business-ready datasets in a third zone for analysts. This layered approach is known as which architecture?
Question 5
A data engineer needs to transform large datasets stored in Azure Data Lake Storage Gen2 using Python and Apache Spark. They want a serverless compute option that automatically scales and requires no cluster management. Which Azure service should they use?
Question 6
A company collects customer feedback forms. Each form contains always-present fields like CustomerID and SubmissionDate, but also a free-text Comments field and optional fields like Rating or ProductCategory that vary between forms. How should this data be classified?
FAQ
Questions learners often ask
What does this DP-900 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: Create a nonclustered index on (Author, PublishedYear DESC) INCLUDE (CopiesAvailable, Title, ISBN). — A nonclustered index on (Author, PublishedYear DESC) covers both the filter (Author) and the sort order (PublishedYear descending). Including the other columns needed (CopiesAvailable, Title, ISBN) as included columns avoids key lookups, making the index covering. Option A includes PublishedYear but does not specify sort order, so the database might still need to sort. Option B filters only on PublishedYear. Option D is not optimal for point queries.
What should I do if I get this DP-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
Loading comments…
Sign in to join the discussion.